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The first indiumsilicate oxysulfide Ba2In2Si3O10S ( 1) was obtained by an alkali polychalcogenide flux method through a high-temperature solid-state reaction. It crystallizes in the non-centrosymmetric space group Pca21 (No. 29), with a = 23.060(6), b = 5.2954(6), c = 8.779(2) Å, and Z = 4. Its three-dimensional (3D) framework is constructed from one-dimensional (1D) infinite ∞1[In2O7S2/2] double octahedral chains bridged by corner-sharing Si tetrahedral trimers [Si3O10]8-, yielding a 3D framework with the channels filled with Ba2+ cations along the b direction. It is unprecedented in that the two distorted indium octahedra in 1 face-share to form a [In2O7S2] dimer in indium oxides and oxide chalcogenides. [ABSTRACT FROM AUTHOR]

A new layered compound, Hg5AsS2I3, has been synthesized in the quaternary system mercury/arsenic/chalcogen/halogen by a moderate-temperature solid-state reaction. The compound crystallizes in the space group C2/ c of the monoclinic system, and its structure consists of ∞1[Hg(1)2Hg(2)2As2/2S2] eight-membered-ring chains bridged by Hg atoms to form [Hg(1)2Hg(2)2Hg(3)As2/2S2] layers with inner- and interlayer electrostatic interactions between I and Hg. The optical properties were investigated by means of diffuse reflectance and FTIR spectra. The electronic band structures, along with density of states (DOS) calculations by DFT, indicate that the title compound is a semiconductor, and its optical absorption mainly leads to charge transitions from I-5p, As-4p and S-3p states to Hg-6s states, and both I(1) and I(2) atoms contribute to the top of the valence bands. [ABSTRACT FROM AUTHOR]